Fix update-ldcache arguments

This change updates how the lconfig arguments are constructed. This
makes the update-ldcache more robust and ensures that folders are
specified last if at al.

Checks are also included for empty container roots at the start of the
hook to simplify later checks.

Signed-off-by: Evan Lezar <[email protected]>

Author: elezar

cmd/nvidia-cdi-hook/update-ldcache/update-ldcache.go

@@ -109,14 +109,20 @@ func (m command) run(c *cli.Context, cfg *options) error {
 	}
 
 	containerRootDir, err := s.GetContainerRoot()
-	if err != nil {
+	if err != nil || string(containerRootDir) == "" || string(containerRootDir) == "/" {
 		return fmt.Errorf("failed to determined container root: %v", err)
 	}
 
 	ldconfigPath := m.resolveLDConfigPath(cfg.ldconfigPath)
-	args := []string{filepath.Base(ldconfigPath)}
-	if containerRootDir != "" {
-		args = append(args, "-r", containerRootDir)
+	args := []string{
+		filepath.Base(ldconfigPath),
+		// Run ldconfig in the container root directory on the host.
+		"-r", containerRootDir,
+		// Explicitly specify using /etc/ld.so.conf since the host's ldconfig may
+		// be configured to use a different config file by default.
+		// Note that since we apply the `-r {{ .containerRootDir }}` argument, /etc/ld.so.conf is
+		// in the container.
+		"-f", "/etc/ld.so.conf",
 	}
 
 	containerRoot := containerRoot(containerRootDir)
@@ -138,10 +144,6 @@ func (m command) run(c *cli.Context, cfg *options) error {
 		args = append(args, folders...)
 	}
 
-	// Explicitly specify using /etc/ld.so.conf since the host's ldconfig may
-	// be configured to use a different config file by default.
-	args = append(args, "-f", "/etc/ld.so.conf")
-
 	return m.SafeExec(ldconfigPath, args, nil)
 }